Tablets containing a cysteine protease, actinidine, reduce oral malodor: a crossover study.

Tongue coating (TC) mainly consists of protein mostly from exfoliated epithelial cells. Until now, to reduce TC accumulation, only mechanical measures have been available, and the procedure involves unpleasant side effects, such as gagging reflex or carcinogenesis related to mechanical stimulation. We expected that protease might be effective in reducing the accumulation of TC causing oral malodor. The purpose of this study was to determine the effect of long-term use of candy tablets containing protease, actinidine, on both TC accumulation and concentration of volatile sulfur compounds (VSCs) in mouth air. We employed 14 subjects aged 24 to 54 years old for this study, and conducted a double-blind randomized crossover trial. The subjects sucked the tablets containing actinidine three times a day until the sixth day after starting the study. The tablets without actinidine were utilized as a placebo. Measurements of VSC concentration and TC accumulation were carried out before and after chewing tablets on the first day, and also on the seventh day. The levels of VSC and TC significantly (p < 0.05) decreased after tablets were taken on the first day in both the test and placebo groups. There was a statistically significant decrease (p < 0.05) in VSC after seven days of use only in the test group. The results of the study suggest that the tablets containing actinidine had an accumulative effect in reducing VSC in mouth air with long-term use.